1. Field Of The Invention
This invention relates to an aluminum alloy, and more specifically an alloy usable in an aluminum anode.
2. Description Of The Prior Art
The use of aluminum alloys in batteries is well known. Aluminum is a preferred material for battery anodes because of its high energy content and low cost. However, problems with voltaic efficiency and coulombic inefficiency have prevented wide commercial use of these aluminum anodes. See U.S. Pat. No. 3,513,031.
It is preferred that aluminum air batteries have high voltage and high coulombic efficiency. However, one of these characteristics is usually sacrificed at the cost of the other characteristic. The use of gallium to increase voltage in aluminum anode alloys is well known. See U.S. Pat. No. 3,393,138 and U.S. Pat. No. 4,150,204. Many aluminum alloys incorporate tin in order to create higher galvanic currents. See U.S. Pat. Nos. 3,282,688, 3,368,952, 3,186,836 and 3,189,486.
It has been known that aluminum reacts with water to release hydrogen. This is undesirable in the battery environment. With respect to this specific problem it has been taught that alloying elements with the lowest melting point will have the highest overpotential for hydrogen evolution. See Comprehensive Treatise Of Electrochemistry, Vol. 2, Chapter 1, Plenum Press (1981).
In spite of these prior disclosures there remains a need for an aluminum anode alloy which produces high voltages, high coulombic efficiency, and resists undesired release of hydrogen which causes gas blockage in the electrolyte passages.